
//**************************************************************************
//**
//** r_plane.c : Heretic 2 : Raven Software, Corp.
//**
//** $Revision: 491 $
//** $Date: 2009-05-30 01:10:42 +0300 (Sat, 30 May 2009) $
//**
//**************************************************************************

// HEADER FILES ------------------------------------------------------------

#include "h2stdinc.h"

#ifndef RENDER3D

#include "h2def.h"
#include "r_local.h"

// MACROS ------------------------------------------------------------------

// TYPES -------------------------------------------------------------------

// EXTERNAL FUNCTION PROTOTYPES --------------------------------------------

// PUBLIC FUNCTION PROTOTYPES ----------------------------------------------

// PRIVATE FUNCTION PROTOTYPES ---------------------------------------------

// EXTERNAL DATA DECLARATIONS ----------------------------------------------

extern fixed_t		Sky1ScrollDelta;
extern fixed_t		Sky2ScrollDelta;

extern byte		*ylookup[MAXHEIGHT];
extern int		columnofs[MAXWIDTH];

// PUBLIC DATA DEFINITIONS -------------------------------------------------

int			Sky1Texture;
int			Sky2Texture;
fixed_t			Sky1ColumnOffset;
fixed_t			Sky2ColumnOffset;
int			skyflatnum;
int			skytexturemid;
fixed_t			skyiscale;
BOOLEAN			DoubleSky;
planefunction_t		floorfunc, ceilingfunc;

// Opening
visplane_t		visplanes[MAXVISPLANES], *lastvisplane;
visplane_t		*floorplane, *ceilingplane;
short			openings[MAXOPENINGS], *lastopening;

// Clip values are the solid pixel bounding the range.
// floorclip start out SCREENHEIGHT
// ceilingclip starts out -1
short			floorclip[SCREENWIDTH];
short			ceilingclip[SCREENWIDTH];

// spanstart holds the start of a plane span, initialized to 0
int			spanstart[SCREENHEIGHT];
int			spanstop[SCREENHEIGHT];

// Texture mapping
lighttable_t		**planezlight;
fixed_t			planeheight;
fixed_t			yslope[SCREENHEIGHT];
fixed_t			distscale[SCREENWIDTH];
fixed_t			basexscale, baseyscale;
fixed_t			cachedheight[SCREENHEIGHT];
fixed_t			cacheddistance[SCREENHEIGHT];
fixed_t			cachedxstep[SCREENHEIGHT];
fixed_t			cachedystep[SCREENHEIGHT];

// PRIVATE DATA DEFINITIONS ------------------------------------------------

// CODE --------------------------------------------------------------------

//==========================================================================
//
// R_InitSky
//
// Called at level load.
//
//==========================================================================

void R_InitSky(int map)
{
	Sky1Texture = P_GetMapSky1Texture(map);
	Sky2Texture = P_GetMapSky2Texture(map);
	Sky1ScrollDelta = P_GetMapSky1ScrollDelta(map);
	Sky2ScrollDelta = P_GetMapSky2ScrollDelta(map);
	Sky1ColumnOffset = 0;
	Sky2ColumnOffset = 0;
	DoubleSky = P_GetMapDoubleSky(map);
}

//==========================================================================
//
// R_InitSkyMap
//
// Called whenever the view size changes.
//
//==========================================================================

void R_InitSkyMap(void)
{
	skyflatnum = R_FlatNumForName("F_SKY");
	skytexturemid = 200*FRACUNIT;
	skyiscale = FRACUNIT;
}

//==========================================================================
//
// R_InitPlanes
//
// Called at game startup.
//
//==========================================================================

void R_InitPlanes(void)
{
}

//==========================================================================
//
// R_MapPlane
//
// Globals used: planeheight, ds_source, basexscale, baseyscale,
// viewx, viewy.
//
//==========================================================================

void R_MapPlane(int y, int x1, int x2)
{
	angle_t angle;
	fixed_t distance, length;
	unsigned idx;

#ifdef RANGECHECK
	if (x2 < x1 || x1 < 0 || x2 >= viewwidth || (unsigned)y > viewheight)
	{
		I_Error("R_MapPlane: %i, %i at %i", x1, x2, y);
	}
#endif

	if (planeheight != cachedheight[y])
	{
		cachedheight[y] = planeheight;
		distance = cacheddistance[y] = FixedMul(planeheight, yslope[y]);
		ds_xstep = cachedxstep[y] = FixedMul(distance, basexscale);
		ds_ystep = cachedystep[y] = FixedMul(distance, baseyscale);
	}
	else
	{
		distance = cacheddistance[y];
		ds_xstep = cachedxstep[y];
		ds_ystep = cachedystep[y];
	}

	length = FixedMul(distance, distscale[x1]);
	angle = (viewangle+xtoviewangle[x1])>>ANGLETOFINESHIFT;
	ds_xfrac = viewx+FixedMul(finecosine[angle], length);
	ds_yfrac = -viewy-FixedMul(finesine[angle], length);

	if (fixedcolormap)
	{
		ds_colormap = fixedcolormap;
	}
	else
	{
		idx = distance >> LIGHTZSHIFT;
		if (idx >= MAXLIGHTZ)
		{
			idx = MAXLIGHTZ-1;
		}
		ds_colormap = planezlight[idx];
	}

	ds_y = y;
	ds_x1 = x1;
	ds_x2 = x2;

	spanfunc();	// High or low detail
}

//==========================================================================
//
// R_ClearPlanes
//
// Called at the beginning of each frame.
//
//==========================================================================

void R_ClearPlanes(void)
{
	int i;
	angle_t angle;

	// Opening / clipping determination
	for (i = 0; i < viewwidth; i++)
	{
		floorclip[i] = viewheight;
		ceilingclip[i] = -1;
	}

	lastvisplane = visplanes;
	lastopening = openings;

	// Texture calculation
	memset(cachedheight, 0, sizeof(cachedheight));
	angle = (viewangle - ANG90)>>ANGLETOFINESHIFT;	// left to right mapping
	// Scale will be unit scale at SCREENWIDTH/2 distance
	basexscale = FixedDiv(finecosine[angle], centerxfrac);
	baseyscale = -FixedDiv(finesine[angle], centerxfrac);
}

//==========================================================================
//
// R_FindPlane
//
//==========================================================================

visplane_t *R_FindPlane(fixed_t height, int picnum,
			int lightlevel, int special)
{
	visplane_t *check;

	if (special < 150)
	{ // Don't let low specials affect search
		special = 0;
	}

	if (picnum == skyflatnum)
	{ // All skies map together
		height = 0;
		lightlevel = 0;
	}

	for (check = visplanes; check < lastvisplane; check++)
	{
		if (height == check->height &&
		    picnum == check->picnum &&
		    lightlevel == check->lightlevel &&
		    special == check->special)
			break;
	}

	if (check < lastvisplane)
	{
		return check;
	}

	if (lastvisplane - visplanes == MAXVISPLANES)
	{
		I_Error("R_FindPlane: no more visplanes");
	}

	lastvisplane++;
	check->height = height;
	check->picnum = picnum;
	check->lightlevel = lightlevel;
	check->special = special;
	check->minx = SCREENWIDTH;
	check->maxx = -1;
	memset(check->top, 0xff, sizeof(check->top));
	return check;
}

//==========================================================================
//
// R_CheckPlane
//
//==========================================================================

visplane_t *R_CheckPlane(visplane_t *pl, int start, int stop)
{
	int intrl, intrh;
	int unionl, unionh;
	int x;

	if (start < pl->minx)
	{
		intrl = pl->minx;
		unionl = start;
	}
	else
	{
		unionl = pl->minx;
		intrl = start;
	}
	if (stop > pl->maxx)
	{
		intrh = pl->maxx;
		unionh = stop;
	}
	else
	{
		unionh = pl->maxx;
		intrh = stop;
	}

	for (x = intrl; x <= intrh; x++)
	{
		if (pl->top[x] != 0xff)
		{
			break;
		}
	}

	if (x > intrh)
	{
		pl->minx = unionl;
		pl->maxx = unionh;
		return pl;	// use the same visplane
	}

	// Make a new visplane
	lastvisplane->height = pl->height;
	lastvisplane->picnum = pl->picnum;
	lastvisplane->lightlevel = pl->lightlevel;
	lastvisplane->special = pl->special;
	pl = lastvisplane++;
	pl->minx = start;
	pl->maxx = stop;
	memset(pl->top, 0xff, sizeof(pl->top));

	return pl;
}

//==========================================================================
//
// R_MakeSpans
//
//==========================================================================

void R_MakeSpans(int x, int t1, int b1, int t2, int b2)
{
	while (t1 < t2 && t1 <= b1)
	{
		R_MapPlane(t1, spanstart[t1], x - 1);
		t1++;
	}
	while (b1 > b2 && b1 >= t1)
	{
		R_MapPlane(b1, spanstart[b1], x - 1);
		b1--;
	}
	while (t2 < t1 && t2 <= b2)
	{
		spanstart[t2] = x;
		t2++;
	}
	while (b2 > b1 && b2 >= t2)
	{
		spanstart[b2] = x;
		b2--;
	}
}

//==========================================================================
//
// R_DrawPlanes
//
//==========================================================================

#define SKYTEXTUREMIDSHIFTED	200

void R_DrawPlanes(void)
{
	visplane_t *pl;
	int light;
	int x, stop;
	int angle;
	byte *tempSource;
	byte *source;
	byte *source2;
	byte *dest;
	int count;
	int offset;
	int skyTexture;
	int offset2;
	int skyTexture2;
	int scrollOffset;

#ifdef RANGECHECK
	if (ds_p - drawsegs > MAXDRAWSEGS)
	{
		I_Error("R_DrawPlanes: drawsegs overflow (%i)", ds_p - drawsegs);
	}
	if (lastvisplane - visplanes > MAXVISPLANES)
	{
		I_Error("R_DrawPlanes: visplane overflow (%i)", lastvisplane - visplanes);
	}
	if (lastopening - openings > MAXOPENINGS)
	{
		I_Error("R_DrawPlanes: opening overflow (%i)", lastopening - openings);
	}
#endif

	for (pl = visplanes; pl < lastvisplane; pl++)
	{
		if (pl->minx > pl->maxx)
		{
			continue;
		}
		if (pl->picnum == skyflatnum)
		{ // Sky flat
			if (DoubleSky)
			{ // Render 2 layers, sky 1 in front
				offset = Sky1ColumnOffset>>16;
				skyTexture = texturetranslation[Sky1Texture];
				offset2 = Sky2ColumnOffset>>16;
				skyTexture2 = texturetranslation[Sky2Texture];
				for (x = pl->minx; x <= pl->maxx; x++)
				{
					dc_yl = pl->top[x];
					dc_yh = pl->bottom[x];
					if (dc_yl <= dc_yh)
					{
						count = dc_yh - dc_yl;
						if (count < 0)
						{
							return;
						}
						angle = (viewangle + xtoviewangle[x])>>ANGLETOSKYSHIFT;
						source = R_GetColumn(skyTexture, angle + offset)
								+ SKYTEXTUREMIDSHIFTED + (dc_yl - centery);
						source2 = R_GetColumn(skyTexture2, angle + offset2)
								+ SKYTEXTUREMIDSHIFTED + (dc_yl - centery);
						dest = ylookup[dc_yl] + columnofs[x];
						do
						{
							if (*source)
							{
								*dest = *source++;
								source2++;
							}
							else
							{
								*dest = *source2++;
								source++;
							}
							dest += SCREENWIDTH;
						} while (count--);
					}
				}
				continue; // Next visplane
			}
			else
			{ // Render single layer
				if (pl->special == 200)
				{ // Use sky 2
					offset = Sky2ColumnOffset>>16;
					skyTexture = texturetranslation[Sky2Texture];
				}
				else
				{ // Use sky 1
					offset = Sky1ColumnOffset>>16;
					skyTexture = texturetranslation[Sky1Texture];
				}
				for (x = pl->minx; x <= pl->maxx; x++)
				{
					dc_yl = pl->top[x];
					dc_yh = pl->bottom[x];
					if (dc_yl <= dc_yh)
					{
						count = dc_yh - dc_yl;
						if (count < 0)
						{
							return;
						}
						angle = (viewangle + xtoviewangle[x])>>ANGLETOSKYSHIFT;
						source = R_GetColumn(skyTexture, angle + offset)
								+ SKYTEXTUREMIDSHIFTED + (dc_yl - centery);
						dest = ylookup[dc_yl] + columnofs[x];
						do
						{
							*dest = *source++;
							dest += SCREENWIDTH;
						} while (count--);
					}
				}
				continue; // Next visplane
			}
		}
		// Regular flat
		tempSource = (byte *) W_CacheLumpNum(firstflat + flattranslation[pl->picnum], PU_STATIC);
		scrollOffset = leveltime>>1 & 63;
		switch (pl->special)
		{ // Handle scrolling flats
		case 201: case 202: case 203: // Scroll_North_xxx
			ds_source = tempSource + ((scrollOffset<<(pl->special - 201) & 63)<<6);
			break;
		case 204: case 205: case 206: // Scroll_East_xxx
			ds_source = tempSource + ((63 - scrollOffset)<<(pl->special - 204) & 63);
			break;
		case 207: case 208: case 209: // Scroll_South_xxx
			ds_source = tempSource + (((63 - scrollOffset)<<(pl->special - 207) & 63)<<6);
			break;
		case 210: case 211: case 212: // Scroll_West_xxx
			ds_source = tempSource + (scrollOffset<<(pl->special - 210) & 63);
			break;
		case 213: case 214: case 215: // Scroll_NorthWest_xxx
			ds_source = tempSource + (scrollOffset<<(pl->special - 213) & 63)
						+ ((scrollOffset<<(pl->special - 213) & 63)<<6);
			break;
		case 216: case 217: case 218: // Scroll_NorthEast_xxx
			ds_source = tempSource + ((63 - scrollOffset)<<(pl->special - 216) & 63)
						+ ((scrollOffset<<(pl->special - 216) & 63)<<6);
			break;
		case 219: case 220: case 221: // Scroll_SouthEast_xxx
			ds_source = tempSource + ((63 - scrollOffset)<<(pl->special - 219) & 63)
						+ (((63 - scrollOffset)<<(pl->special - 219) & 63)<<6);
			break;
		case 222: case 223: case 224: // Scroll_SouthWest_xxx
			ds_source = tempSource + (scrollOffset<<(pl->special - 222) & 63)
						+ (((63 - scrollOffset)<<(pl->special - 222) & 63)<<6);
			break;
		default:
			ds_source = tempSource;
			break;
		}
		planeheight = abs(pl->height - viewz);
		light = (pl->lightlevel >> LIGHTSEGSHIFT) + extralight;
		if (light >= LIGHTLEVELS)
		{
			light = LIGHTLEVELS-1;
		}
		if (light < 0)
		{
			light = 0;
		}
		planezlight = zlight[light];

		pl->top[pl->maxx + 1] = 0xff;
		pl->top[pl->minx - 1] = 0xff;

		stop = pl->maxx + 1;
		for (x = pl->minx; x <= stop; x++)
		{
			R_MakeSpans(x, pl->top[x - 1], pl->bottom[x - 1],
					pl->top[x], pl->bottom[x]);
		}
		Z_ChangeTag(tempSource, PU_CACHE);
	}
}
#endif	/* !RENDER3D */

